HR: 11:44h
AN: A22B-07    [Abstracts]
TI: Clouds Aerosols Internal Affaires: Increasing Cloud Fraction and Enhancing the Convection
AU: * Ilan, K
EM: ilank@climate.gsfc.nasa.gov
AF: JCET, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 United States
AU: * Ilan, K
EM: ilank@climate.gsfc.nasa.gov
AF: Climate and Radiation Branch, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Kaufman, Y J
EM: yoram.j.kaufman@nasa.gov
AF: Climate and Radiation Branch, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Remer, L A
EM: Lorraine.A.Remer@nasa.gov
AF: Climate and Radiation Branch, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Rosenfeld, D
EM: daniel@vms.huji.ac.il
AF: Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904 Israel
AU: Rudich, Y
EM: yinon@wisemail.weizmann.ac.il
AF: Department of Environmental Sciences, Weizmann Institute, Rehovot, 76100 Israel
AB: Clouds developing in a polluted environment have more numerous, smaller cloud droplets that can increase the cloud lifetime and liquid water content. Such changes in the cloud droplet properties may suppress low precipitation allowing development of a stronger convection and higher freezing level. Delaying the washout of the cloud water (and aerosol), and the stronger convection will result in higher clouds with longer life time and larger anvils. We show these effects by using large statistics of the new, 1km resolution data from MODIS on the Terra satellite. We isolate the aerosol effects from meteorology by regression and showing that aerosol microphysical effects increases cloud fraction by average of 30 presents for all cloud types and increases convective cloud top pressure by average of 35mb. We analyze the aerosol cloud interaction separately for high pressure trade wind cloud systems and separately for deep convective cloud systems. The resultant aerosol radiative effect on climate for the high pressure cloud system is:-10 to -13 W/m2 at the top of the atmosphere (TOA) and -11 to -14 W/m2 at the surface. For deeper convective clods the forcing is: -4 to -5 W/m2 at the TOA and -6 to -7 W/m2 at the surface.
DE: 3300 METEOROLOGY AND ATMOSPHERIC DYNAMICS
DE: 1600 GLOBAL CHANGE (New category)
DE: 1610 Atmosphere (0315, 0325)
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting